Help! My 04 Maxima SE cranks but won't start
 

Changed the valve covers and spark plugs because the car was leaking oil, but when I tried turning the car on it cranked but didn't start. Made sure all sensors and grounds were in place. Put it on a scanner but it didn't throw any codes. Changed the CKPS and the cam sensor and then also the fuel pump. Already checked the relays and the fuses and they're all okay. Managed to get it to start twice but the engine shut off in a matter of seconds. The fuel pump is working and has pressure, but my spark plugs aren't sparking. What should I do??? 😓 :confused: